My goal is to understand the molecular mechanisms operating during early development. Homeobox genes are known to play important roles during embryogenesis. A homeobox gene, msx2, has been shown to be expressed at numerous sites of epithelial-mesenchymal interactions e.g. in the developing limb buds, heart primordia and the facial processes during early development. The purpose of my study is to understand the molecular mechanism of action of the msx2 gene by using the Xenopus laevis system. I have preliminary data to show that the msx2 gene is involved in defining the ventral mesodermal pathway of the developing Xenopus embryo. My hypothesis is that the msx2 is one of the molecules that refines the ventral mesoderm. Experiments are currently in progress in the laboratory to overexpress the msx2 gene in developing Xenopus embryos, to characterize the other molecules in the ventral mesodermal pathway as well as to clone and characterize the Xenopus homolog of the msx2 gene.